Thermal oxidation is a process commonly used to deposit high purity and highly conformal silicon oxide films such as silicon dioxide (SiO2) in semiconductor applications. However, the thermal oxidation process has a very low deposition rate, e.g., than 0.0007 Å/s at 700° C. (see B. E. Deal and A. S. Grove “General Relationship for the Thermal Oxidation of Silicon.” Journal of Applied Physics Vol 36, page 3770 (1965)) which makes it impractical for high volume manufacturing processes to be commercially adopted.
Atomic Layer Deposition (ALD) and Plasma Enhanced Atomic Layer Deposition (PEALD) are processes used to deposit silicon dioxide (SiO2) conformal film at low temperatures (<500° C.). In both ALD and PEALD processes, the precursor and reactive gas (such as oxygen or ozone) are separately pulsed in certain number of cycles to form a monolayer of silicon dioxide (SiO2) at each cycle. However, silicon dioxide (SiO2) deposited at low temperatures using these processes may contain levels of impurities such as carbon (C), nitrogen (N), or both which are detrimental to semiconductor applications. To remedy this, one possible solution would be to increase the deposition temperature to a temperature greater than 500° C. However, at these higher temperatures, conventional precursors employed by semi-conductor industries tend to self-react, thermally decompose, and deposit in CVD mode rather than ALD mode. The CVD mode deposition has reduced conformality compared to ALD deposition, especially for semiconductor applications that have high aspect ratio structures such as NAND and V-NAND. In addition, the CVD mode deposition has less control of film or material thickness than the ALD mode deposition.
US Publ. App. 2014/0170858 describes a method of forming a film including a predetermined element, oxygen and at least one element selected from a group consisting of nitrogen, carbon and boron on a substrate by performing a cycle a predetermined number of times, the cycle including supplying a source gas to the substrate wherein the source gas contains the predetermined element, chlorine and oxygen with a chemical bond of the predetermined element and oxygen, and supplying a reactive gas to the substrate wherein the reactive gas contains the at least one element selected from the group consisting of nitrogen, carbon and boron.
US Publ. App. 2007/0111545 describes a method of forming silicon dioxide layers using ALD to enhance deposition rate and improve step coverage in semiconductor device fabrication.
U.S. Pat. No. 7,498,273 describes a method of depositing a low-K dielectric layer in a gap formed on a substrate are described using siloxanes in PECVD which give films with low porosity, high etching selectivity, and fewer cracks. The methods include introducing an organo-Si precursor and an O precursor to a deposition chamber. The organo-Si precursor has a C: Si atom ratio of <8, and the O precursor comprises atomic O that is generated outside the deposition chamber.
U.S. Pat. No. 7,084,076 describes a method for forming a silicon dioxide film using atomic layer deposition (ALD), wherein a halogen- or NCO-substituted siloxane is used as a Si source.
US Publ. No. 2013/0295779 describes a composition and ALD for forming a silicon oxide containing film at one or more depositions temperatures of about 500° C. or greater.
The previously identified patents and patent applications are hereby incorporated by reference.
Thus, there is a need to develop a process for forming a high quality, low impurity, high conformal silicon oxide film using an atomic layer deposition (ALD) process or an ALD-like process, such as without limitation a cyclic chemical vapor deposition process, to replace thermal-based deposition processes at temperatures above 600 C for Vertical NAND (V-NAND) memory technology. Further, it may be desirable to develop a high temperature deposition (e.g., deposition at one or more temperatures of 650° C. or higher) to improve one or more film properties, such as purity and/or density, in an ALD or ALD-like process for the fabrication of V-NAND memory.